Hyoudou's secret
by Zeyho
Summary: Issei dissapeared after a fight with a stray demon. After a month full of hopes Issei returns home togheter with his big brother Ryo. But what if Rias actually knows Ryo from her first year of high school? Can Issei stop Ryo from stealing his harem by accident or would Rias change her favourite chess piece? [OC x Rias][a litle OC x Akeno]
1. Chapter 1

A week has passed since her beloved pawn had just vanished from her and his parents life. No call,no letter not even a sign that the boy still existed in this world. She searched the hole human wolrd and the hole Hell for him with no success. Slowly she lost her fate, once again the one she cared about just vanished when she needed him the most. In wasn't enough that she had to put up with the arrangement her family made for her to marry Phoenix after what she been through but now Issei had to dissapeare. Rias was completely lost,Akeno and the others were also scared for both Issei and their master.

Thee weeks had passed to the point when no one could even think that Issei is still alive but something amazing happened. It was another sad afternoon in the Hyoudou house,Rias and Asia where there with his parents having lunch when someone knocked on the door. Issei's mother answered the door and screamed. The others went to see what happened just to be shocked aswell,Rias was shocked and Asia was smiling. Issei was there, safe and alright, togheter with another boy - his big brother whom no one spoke to for 2 long years. Their mother embraced the two in a tigh hug and their father started to question them. Issei explained that he passed out for almost two weeks and was found by his brother who took him to a particular clinic. As Issei finished the explanations Rias was looking into the mysterious brother's eyes,they were black just like Issei's but much more deeper, the look in the boys eyes actually remind her of her father's - deep and very frightening -,focused on her own person. A familiar feeling appeared in his eyes,he smiled at her with a much relaxed look in his eyes. His smile was warm and cute but he remembered her about her father's story about the Hell prince,fallen angel Lucifer's son. Lost in thoughts she didn't feel the boy getting closer to her or Asia who began to tremble a litle.

"Still as red as always,right Rias?" the boy asked taking a set beside the red headed girl. Rias was a litle shock about the boy's question but then her eyes widened as she finally recognize the boy. He was so changed now,the small, fragile boy she once befriend was now a tall,very well build and very good looking young man. She smiled and laughed as Issei jumped to his brother and asked him how does he know her. Rias stoped Issei and explained that she knew his brother from the first year of high school when they accidentally became friends and later on a couple. Still a litle shocked she took another look at the boy. Indeed, he was now a whole new person in appearance. His dorky look was replaced with a more sober black rock style and his short brown hair was a litle longer and now black but the look in his eyes was still pure and inocent. Yes,his appearence was totally changed but his soul and mind were still as she remembered. Between two momemnt in wich she could stop herself from smiling she asked him that she wanded to talk with him alone in her room. After they made it into her room they began to talk and listen to some of the songs from his actul favorite band, he told her about the placed he been through and about the people he meet, about how sorry he was for just dissapear and about how he missed her and the old band. In exchange she told his about the school years and the things he missed in 2 years, about how glad she was that he was back and ok and about how she missed him. They talked for hours until 2 o'clock in the morning when he decided to let her rest a litle, he helped her up the floor they been sitting on and kissed her forehead as a good night, she smiled at him and kissed him back on the cheek. Both were trilled to see eachother, especially her since from this day on he was going to be in the same class as her.

After he leaved to his old room she was more than excited that he camed back exactly when she needed him,she couldn't wait for morning to came so she could spend time with him again hoping no one would came and ruin her day with some devil work or with another discussion about the fact that she is a devil and he is a human.

He was just as exited as her,now he was strong enough to be able to be by her side. He was even more happy to see how beautiful she became and that her personality was unchanged. He couldn't wait for morning to came so he could make her skip class and spend the day togheter hoping no one would ruin their day with a call from his 'boss' ordering him around like he always does.


	2. Chapter 2

A tipical morning in the Hyoudou house. Issei's clock started to ring making both Issei and Ryo,whose room was right next to Issei's, wake up. Issei woke up next to Asia who,luckily was fully dressed, this time but usually he would wake next to the Prez. Issei got out of bed and got dressed without waking Asia up. As he was about to wake Asia up and ask her what happened with the Prez someone knock hard on the door. He slowly opened the door to see the Prez wearing only a black t-shirt with a big "F_CK, all I need is U" that was 2x her size,at first he didn't knew from where did she got it but then the light was turned on in his head,the t-shirt belonged to Ryo. Issei never suspected that Prez knew Ryo so the shock of them going out in their freshmen year still took afect on him. Rias was in a very good mood,she woke up Asia and went downstairs for breakfast.

Ryo came shortly after that. He wasn't wearing a shirt, only a black pair of jeans and his favorite pair of black shoes. He was still half asleep and his hair was a total mess, he took a sit on the chair next to Rias and smiled and Issei could observed the blush in the Prez's cheeks as she looked at his brother. Even Issei had to admit that his brother far surpased him,even with the training from Prez he wasn't even close to his brother's level. Ryo was well builded because of the basketball trainings, he was rather skinny but that only made his muscles hardened up more. But something jumped in his attention, his brother had two tattoos on each of his arms,they were rather simple,only medium black circles, one om his forearm and one a litle higher up just below his shoulder, he wanted to know why Ryo got tattoos but his mother told them to go get ready for school. Issei,Asia and Rias got dressed fast but Ryo couldn't decide on what he should wear. The gave up and took his black V-neck classic shirt with tassels neck warmers that was a litle longer in front,black slim skinny jeans and black leather converse all star and a sleeveless hooded leather jacket and a black simple snapback cap to match the outfit but Ryo had a hard time arranging the cap because of his messy hair.

Issei and Rias started to became inpatient waiting for their friend. "What's taking him so long?! Geez, that idiot..." said Rias as she went after Issei's brother. As she entered Ryo's room she saw the boy cursing in the mirror as he was trying to arrange his cap. She looked surprised at the boy as she blushed furiously, the last night she was too tired to observe all the details that made him look even more amazing. She smiled at his nervous look and got closer to him asking "Need any help?" as the boy jump surprised. "Sorry did I scare you?"

"Nah,I was just surprised that's all. And yeah, I guess I need a litle help,if you don't mind." the boy turned to face her with his face inches away from hers. Ryo was blushing a litle as he looked away avoiding eye contact, he closed his eyes and began to think about something else. His thoughts were interrupted by a quick peck on the lips, Ryo blushed furiously as he opened his eyes to look at Rias who was also blushing as furious as him. "R-Rias...why did you..."

"S-Sorry... I don't know what got into me, I just... I just missed you so much and..." she couldn't finish the phase because she was pushed into the wall and pulled into a long kiss. At first she oppose but she slowly lost herself into the kiss. After some minutes Ryo pulled back and smiled, Riss was still shocked but she was happy that her former boyfriend still had strong feelings for her, she smiled as she gave him another quick peck on the lips before they went to school.

Of course the other students would consider Issei filthy for walking next to the school's top idol, Ryo could even hear some boys cursing his litle brother, but now came his turn to be in the middle of attention. He was ready to hear bad things but instead the girl just stared at him I surprise, some even cursed Rias?! for walking next to, according to them,was a model or something. Ryo laughed as Rias was blushing to the constant girl telling her how lucky she is to have such a handsome boy at her side. As she and Ryo got into their class Rias was took by a group of girls for interrogation and Ryo simply looked for a empty chair to sleep.

Classes went pretty fast for Ryo who wasn't paying attention to the teachers but to Rias all the time, the kiss was repeating in his head, wich made him smirk every time she looked in his direction. The day ended quick and Rias, Issei, togheter with Ryo went to the Occult Club. Ryo was greeted by Akeno who was very surprised to see him there,the others were surprised as well,getting a human into this room was very risky but for some reason Rias didn't seem to care too much, neither did Akeno or Koneko. It was an unusually silence afternoon, all the club did was to simply talk,Rias and Akeno were all over Ryo questioning him about his leaving. Issei sighed, his brother got both Rias and Akeno's attention with a mere show up. The things went like that for some more minutes until Rias's expression changed into a one of concern right before a magic circle of the Gremory clan appeared and her brother showed up with Grayfia.

"How are things going,litle Rias?" said her brother with a smile before seeing Ryo. His smile faded away into a neutral look before he spoke up again "What is this human doing him?"

"Brother,you should have told me that you were visiting! This is, um..." Rias lost her words, how could she explain that Ryo was her boyfriend who hates devils from the bottom of his heart, or that she was a devil? She was afraid that Ryo would make a scene but he,wasn't moved at all,he was calm and not bothered by the sudden appearing.

"Well,this human was a name you know? Nobility doesn't have manners these days or what? And I'm Ryo Hyoudou, Issei's big brother." everyone was surprised at the boys reaction especially Rias, her hand was already shaking a litle but Ryo putted his hand on hers as he stood up and gave her a kiss on the cheek. "Now may I ask what is the purpose of this visit?"

After all of them took a sit Rias's brother explained that a unknown powerfull devil was wandering here because of a sudden energy burst that accumulated here and that for some days he would stay at the Hyoudou's house. Both Rias and Issei jumped on that complaining,the answer was a simple one,Sirzechs told them that he was going to stay whatever they said to keep an eye on Ryo. Ryo smiled as Sirzechs told that but Rias was sad,if her brother is there she couldn't made a move toward Ryo anymore. As Ryo checked his phone he excused himself and leave in a hurry after he gave Rias a kiss on the lips making Sirzechs and Issei angry.

It was already dark when Sirzechs finished all the details about the mission. A strange energy apeared out of nowhere and all when to face the so called devil. Rias and Akeno arrived first at the abandoned building, they entered with caution the empty room. As they looked around Ras suddenly screamed at was she just saw,Ryo was lying on the ground with his left arm cut up, she covered her mouth as she fell on the ground crying. When the others arrived the energy was no longer there,Rias was still in shock over Ryo's dying body, Issei fell on the ground beside Akeno who was also in shock. Sirzechs went next to Rias and pulled out a mutant knight piece "You can save him if you want..." but Rias didn't approved.

"Brother Ryo hates devils! And even if I would his arm can't be healed! "

"His arm will be healed, miss Rias. This young boy has a huge potential of becoming the strongest knight. "

"Grayfia...what are you talking about? " asked Sirzechs

"It took a while for me to observe but the boy looks exactly like Prince Hell, Lucifer's first son. If I am correct this boy could be the strongest devil of all times."

Rias took some time to think,Ryo hated devils but she didn't wanted to loose him,not again. She took a breath and started the ritual to transform Ryo into a devil. An overwhelming energy surrounded Ryo's body as blue flames appeared in the place his arm should be, healing his arm. Rias stared at Ryo's body covered in flames,the energy emitted from them were over even Sirzechs's powers. The flames were off fast as Ryo was recovering from the mortal blow that almost ended his life,his head was hurting like hell and his vision was blurry. Rias rushed to his side helping him up as she explained how was it that he was still alive. At fist the boy was confused but then he stoped Rias when she wanted to apologize for transforming him into a devil.

"Chill out,you didn't transforme me,you just activate the devil blood that's inside my body. Thanks Rias." Rias started crying as he embraced her, she always felt same in his arms but now even if he was a devil that sensation didn't change,it was still as warm and as lovely as she remembered. Taking advantage of the situation Ryo stole a kiss from Rias,making her blush furiously as she asked for an entrance wich he gladly accepted.

"Ahem...Would you mind telling us who you really are,Ryo?" Sirzechs said as he was glaring at the boy. Ryo sighed and took a step away from Rias.

"As Grayfia already said I am Lucifer's first son,the prince of hell. And before you ask anything else my original name is Ryuuzei Lucifer Hell,but I don't use my father's name so just ignore the Lucifer from my name." he said before Rias hit him for lying to her. "Sorry Rias,but if anyone would've found out you would've been in danger... Please forgive me." he continued as he bowed before her.

Rias was surprised but Ryo,no,Ryuuzei was right,if anyone would've found out someone would've come after him,someone stronger than her that would've probably killed her. She hit him in the head again,he got up and smiled right before she kissed him again. The moment didn't last very long because Sirzechs told Ryuu that if he hearts his sister he would die. Rias blushed and yelled at her brother as Grayfia hit him for telling something like that. Ryuu laughed as she embraced Rias again and kiss her.

"I think the fun is just about to begin,righ Prez?" Rias blushed again as her newly knight kissed her neck.

"It would be interesting to live with you and Issei...I'm glad you are alright. But Ryuu,as punishment from now on you will be living with me after all,I have to punish my servants when they lie to me... " said Rias to a confused Ryuuzei,she smiled as well when he realised what she just said and smiled. "Too much for you, Ryuu?"


	3. Author note 1

Since I kinda confused you with the second chapter I wanted to give some explanation,also a litle explanation of why does Issei's brother "steals" Rias and Akeno(just Rias) from Issei :

1. Ok,so a litle explanation of how the idea came up. I though thatit will be cool if Issei actually had a brother that is related to the original Lucifer to make things a litle more interesting. At first I wanted to make Ryuu Raiser's knight so that Raiser could use him to mental defeat Rias but I'm not that evil yet...

,in the description I said "stealing his harem BY ACCIDENT". Even so I didn't really meant that,I actually meant that Rias had feeling for Ryuu from the first year of high school and Akeno was the one that technically bring Ryuu and Rias togheter buut Akeno also took a liking on Ryuu,of course only as for a litle brother.

and Issei aren't directly related by blood,Ryuu was left on the stairs of Issei's house when he was very litle and Issei's power took him in,but in their childhood Issei got badly injured and needed a blood transfusion from Ryuu and so he obtained some of Ryuu's powers that are sealed inside him.

on I'm gonna have a look inside Ryuu and Rias's future so there might be a more indecent scene but I'm not going to actually have them do it...I'm a litle spoiler...


	4. OC Bio

**Ryuuzei Lucifer Hell**

Ryuuzei Hell,formerly known as Ryo Hyoudou,is the first son of the Original Lucifer and greatuncle of Vali Lucifer. As Satan's first son Ryuuzei,also known as Prince Hell,was the original future-ruler of the Underworld but at the age of sixteen he gave the title of "Lucifer" away to the Gremory clan and retired from the devil work. Ryuuzei kept in touch with Sirzechs and Grayfia,who at that time was his servant,but as the years gone by Ryuu had to vanish leaving Grayfia and his peerage into Sirzechs's care.

**_APPEARENCE_**

Ryuuzei is a handsome young man,having the appearance of a man before his early 20's with short dark brown hair and black eyes. Though he is well train and very agile his body isn't very muscular,having a rather skinny body. His hairstyle meet a large variation because of his fast changing mood.

_**PERSONALITY**_

Ryuuzei s shown to be kind and caring towards other,especially to his peerage and Rias,and prefer to have things sorted out through talking instead of fighting. Despite being the son of Lucifer,Ryuu has a very laid-back personality, preferring to do things at his own pace withouth anyone getting in his way or interfearing with his way of thinking,however,Ryuu does have a serious side wich he almost never shows.

_**PROFILE**_

Race : Pure-Blooded Devil

Nicknames : Prince Hell(title)  
>Satan Black<p>

Hair Color : Dark brown

Eye Color : Black

Equipment : Immortality  
>Pyrokinesis<br>Blue Flames of Satan

Relatives : Unnamed Parents  
>Issei Hyoudou(brother)<p>

Affiliations : Occult Research Club  
>Hyoudou Residence<br>Rias Gremory's Peerage  
>Anti-Satan Faction<br>Satan Rangers  
>Four Great Satans(former)<p>

Status : Alive

Ranking : Satan(Lucifer)  
>KingKnight(1xMutation Piece)  
>Super Devil<p> 


	5. Chapter 3

It was the fifth time Rias was woke up by Issei's clock this week. She sighed and started to get up when she was dragged back on the bed,back into a pair of strong arms. She smile when she heared the soft,low groan from a certain brown haired teen. She started laughing hard when the teen kissed her sweet spot.

"S-Stop! R-Ryuu,I can't beath!" she cried through the laughs. She liked it but she was to tired to play along since last night she stayed up all night to help her brother. She hitted the boy in his stomach making him stop. "Geez...what got into you this early?"

"Don't blame me,I've been trying to spend some time with you the whole week but your brother or Issei always get in the way..." replied the teen angrily while rubbing his stomach "And really Rias did you have to hit THAT hard?" continued as he got up and went to check his phone and change

Rias turned brigh red from the emberasement "Sorry... It just I've been up all night with my brother and..." she was stoped by a pair of lips capturing her own and pressing her on the bed.

"And...? Rias,let's go away some days and relax..." he said as he got up and kiss her forehead

"I can't... I have a duty as a Gremory. Ryuu you are a high class devil I'm sure you know how important this duty is."

-sigh- " I know... But next time ask me for help,I know how hard it's to work all night,ok?"

"Thanks..." Rias replied as the two started a mini-makeout session

"Ahem..." both Rias and Ryuu jumped, Rias turned away while the boy hit the floor hard,when Grayfia show up

"Damn it Grayfia! Want to kill me or something?!"

"Apologises but Rias-sama has to atend a meeting togheter with her peerage."

"A meeting with?"

"Ryuuzei-sama this information I cannot give,please understand and let Rias-sama go..." said Grayfia as Ryuu got up putting a serious face

"It would be pointless to argue with you so let's just go..."

"Ryuuzei-sama,I already told you that these meeting is for Rias-sama and her peerage. I do know that you are her knight but Lucifer-sama does not approve your presence at the meeting."

"Why's that? I am part of her peerage and it's my duty as her knight to protect her."

"Enough you two...Grayfia,Ryuu is right he is my knight so let's just end this disscution and let us change."

"Yes,Rias-sama. Please hurry."

As Grayfia dissapeared into the magic circle Rias throw herself onto the bed sighing loud. Ryuu took a sit next to her reaching for her hand.

"Whatever your brother wants I'm here and I'll protect you..."

"I know Ryuu..." Rias sighed again before Ryuu kissed her again and start changing.

-AT THE CLUB ROOM-

"Ok what was so important Grayfia?" Ryuu asked as he took a sit on the desk and Rias on the chair

"Lucifer-sama arranged a meeting to settle things between Rias-sama and Pheonix-sama."

"WHAT?" Rias shouted as she jumped out of the chair next to Grayfia. A magic circle appeared and a blond man appeared from it.

"My dear Rias,Reiser is here. How are you?"

"Your dear Rias?" Ryuu asked as he glared at the man while he took his place as knight next to Rias.

"Hmm? And who may you be to ask Reiser a question,you low devil?"

"What did you just call me you ass?!" Ryuu took a step toward Reiser just to be stopped by Rias with a peck on the lips. Ryuu calmed down and put a possesiv arm around his 'king'. "I'm Ryuuzei Lucifer Hell. And your majesty is?" he asked in a sarcastic tone.

"I am the great Reiser of the Pheonix. How dare you speak like that to a pure-blood,and how dare you kiss Reiser's fiancee?!"

"Excuse me? Isn't your IQ a little too below zero to question Satan's son?"

Reiser's eyes wide in shock. Grayfia smiled at the boy and Rias gave him another kiss before speaking.

"Reiser I already told you that I have no interess in marrying you. If my family wants me to marry a pure-blood then Ryuu is my choice."

"And if you are still agains that Reiser,a Rating Game would be enought to make you shut up..."

"I doubt that you actually have a peerage but I will accept you're chalenghe! We shall face in a week."

With that Reiser left and Rias began to shoute at Ryuu "Do you at least have a peerage?!"

"Of course,a full set actually. All of them high-devils so you don't have why to worry. Now,what did you say about choosing me?" he didn't wait for an answear as he dragged Rias in a long kiss.

"I apologise for intrerupting you but Ryuuzei,where is your peerage? You've been gone for a long time..."

"Shattered around the country. Each of them trained on his own when I was gone. I meet them some days ago so they are good to go and ready for revenge on the Pheonix clan.." Ryuu said with a devilish smirk

"That smirk of your means you have a plan... I don't even want to know Ryuu..."

"It would be for the best if you don't. After all I'm gonna beat the crap out of that idiot in less than ten seconds..." Ryuu smirked devilishing as Rias gluped

"Ok,ok... Could someone explain us what the hell just happen?!"

"O-Oh,of course... My father arranged a marriage between me and Reiser. I've been agains it from the beginning but Reiser is very persistent."

"He won't be after I kick that ass of his... Anyway I should be off meeting with my queen..."

"Can't I-WE meet her? I mean,if it's you queen I bet she is strong and we could learn something from her..."

"Hmm... Good idea." Ryuu snaped his fingers and a black portal began to glow. Ryuu smile as his queen began to appeare.

A blond girl,about the same heigh as Rias,with black eyes dressed in a school uniforme stepped out of the portal "Geez Ryuu... What's up? I tough we would meet up alone..."

"Sorry,but they wanted to meet you. Guys this is my queen,Amelia."

"It's nice to finally meet the heir of the Gremory Clan. I assume that my King is in good hands..." all the girls,except Asia,looked at eachother and began to laugh

"Amelia! That is not a question to ask! And why are you laughing?!" yelled Ryuu to Rias before he began to laugh too


End file.
